In the last four to five years microdentistry began to develop. Microdentistry is the performing of dental surgery and procedures with very small tools under a microscope. As an example, in the preparation of root canals, it has been found that the tool must be very small in order to work in the small canal areas. Such small tools must also be very strong and touch and able to withstand and/or easily dissipate and/or resist heat.
In recent years ultrasonic tools have been developed which many dental surgeons have begun to use for many operations on teeth, bones, and soft tissue including dislodging and removal of dental material. These ultrasonic tools have been found to be particularly useful for microdentistry and particularly for use in root canals. Tools for this purpose must be small, hard, durable and heat resistant in order to satisfactorily perform their function. They must also be flushed with a fluid such as water to dissipate heat and flush away debris.
Recent years have seen greater use of ultrasonically powered instruments for the preparation of root canals. Examples of ultrasonically powered instruments of this type for the preparation of root canals are disclosed in U.S. Pat. No. 4,019,254, issued Apr. 26, 1977 to Malmin, U.S. Pat. No. 5,094,617 issued Mar. 10, 1992 to Carr and PCT Publication WO 86/05967. With the exception of the first mentioned patent, all tools are formed with a shaft tapered to a point. More recent examples of improved tools are disclosed in the applicant's recently issued U.S. Pat. No. 5,836,765, issued Nov. 17, 1998, and U.S. Pat. No. 5,868,570 issued Nov. 12, 1998 to Hickok.
Most dental tools and work areas are cooled with a continuous stream of water during use. Cooling in this manner is not always possible, particularly when working in certain small confined areas such as root canals, and in most instances this form of cooling is inconvenient.
In the past, fluid such as water has been supplied to the cutting tool by means of either a separate water supply such as a wand or the like, or a supply through or from the adjacent power unit. The tools normally used with ultrasonic generators are typically very small and must be hard and durable to withstand the high energy delivered by the ultrasonic generator. Due to the size and the materials from which the tools are made, it has not been possible to provide a through the tool fluid supply to the tool and word area.
One example of an earlier dental tool having a fluid supply to the tip is U.S. Pat. No. 3,924,335 dated Dec. 20, 1975, The patent discloses a metal or plastic transmission member which has a water feed to be used as a dental prophylaxis unit for removing deposits from tooth and gingival surfaces. However, this tool is not suitable for microdentistry.
U.S. Pat. No. 4,193,196 discloses a fluid supply unit for dental instruments wherein an instrument is shown with flow through tip. This tool is not disclosed as suitable for microdentistry.
U.S. Pat. No. 5,733,119 discloses a dental tool having fluid supply port in the hub of the tool. These tools of the prior art cannot be made sufficiently small to function as a microdentistry tool and provide the fluid port in the shaft of the tool at the working tip.
Therefore, there is a need for an improved ultrasonic dental tool formed of a suitable strong, flexible and durable heat resistant material with suitable fluid port for microdentistry.
Another drawback to these tools is that they are attached and detached from the hand piece of the ultrasonic generator by means of a threaded connection requiring a wrench or other special tool. This is particularly inconvenient because several different shape tools are frequently required during any particular operation.
Therefore, there is also a need for an improved ultrasonic dental tool having a quick attach connector for microdentistry.